You'll probably (certainly) have to use the parent-child animation feature. The rover body and everything attached to it is an animated part, and superstructure like the head mast and antenna should be "secondary" animations children of the "rover body rising" animation. It is a bit complex, but the SDK certainly allows it. Stock Atlantis RMS does something alike.
For the attachment point it is a virtual thing, that has no connection with the mesh. It is simply a way to keep the rover and the lander linked together. In this regard it is simpler than Atlantis RMS. It is probably best I have the lander "shift" and rotate its (parent) attachment point, allowing to simulate the "down the ramp" sequence. Rover will be the child.
So yes, there's a bit of hierarchy. Lander (separate vessel) is parent to the rover (both are connected by an attachment point - attachments point in Orbiter work with parent/child logic -, rover wheel legs are parent to the rover body, and the rover body is parent to other stuff like mast or antennas.